Safari, Opera browsers patch-shy, says study

Chrome, Firefox users plug more often

Users of Safari and Opera are much more likely to run insecure versions of those browsers because it's harder to keep up with updates, a new study has concluded.

The report, prepared by researchers at Google Switzerland and the Swiss Federal Institute of Technology, analyzed data pulled from anonymized Google logs. It showed that only 24 percent of Opera users were browsing with the latest version three weeks after a new release. Apple's Safari fared slightly better, with 53 percent of users on a 3.x version of Safari having applied a new update within 21 days.

"All in all, the poor update effectiveness of Apple Safari and Opera gives attackers plenty of time to use known exploits to attack users of outdated browsers," the report's authors, Thomas Duebendorfer and Stefan Frei, wrote.

By contrast, Google Chrome and Mozilla Firefox did much better, with 97 percent and 85 percent of users running the most current browser respectively. Microsoft's Internet Explorer was excluded from the comparison because its user-agent string doesn't reveal incremental versions numbers.

The authors concluded that the differences were largely the result of the way the browsers go about offering updates. Both Chrome and Firefox offer autoupdates that go largely unnoticed by users. In the case of Chrome, the browser automatically checks for new versions every five hours. When one is detected, it is downloaded and installed the next time the user restarts the browser. Firefox checks for updates each time the browser is started, and when one is found, the user is asked to reboot the program.

Apple and Opera don't make things as easy, the authors say. Those running a 3.2 version of Safari on a Mac must apply a Tiger or Leopard operating system update first before getting browser updates, which slows the overall patch process. Opera checks for updates only once a week, and users have to go through a fresh installation each time one is found.